I think you are overestimating the impact the pandemic has on the economy and political relationships between the countries.
Yes, the poor will become poorer, but rich countries have suffered as well, only their economy is more stable, so they won't be so damaged.
Rich countries will becoming more richer while poor will becoming more poor especially if the vaccines for covid19 purchase through debt.
But this is too much.
There is a possibility that after these pandemic another country will begin to colonized other country and no one could help because they had huge resources especially for war.
For decades rich countries have provided help to the poorer ones and they're already in huge debts because of wars, trading issues, corruption schemes running, etc. This help, however, is dictated by law and certain existing agreements between countries that are in certain unions and memberships. This does not mean that poor countries will have to subordinate themselves to the rich.